Stockholders' Equity (Details) - USD ($) $ in Millions	3 Months Ended
	Jul. 31, 2022	Jul. 31, 2021
Beginning balance	$ 2,737	$ 2,656
Net income	249	192
Net other comprehensive income (loss)	1	8
Declaration of cash dividends	(180)	(172)
Stock-based compensation expense	4	4
Stock issued under compensation plans	4	5
Loss on issuance of treasury stock issued under compensation plans	(8)	(10)
Ending balance	2,807	2,683
Additional Paid-in Capital [Member]
Beginning balance	0	0
Stock-based compensation expense	4	4
Loss on issuance of treasury stock issued under compensation plans	(4)	(2)
Ending balance	0	2
Retained Earnings [Member]
Beginning balance	3,242	3,243
Net income	249	192
Declaration of cash dividends	(180)	(172)
Loss on issuance of treasury stock issued under compensation plans	(4)	(8)
Ending balance	3,307	3,255
AOCI Attributable to Parent [Member]
Beginning balance	(352)	(422)
Net other comprehensive income (loss)	1	8
Ending balance	(351)	(414)
Treasury Stock, Common [Member]
Beginning balance	(225)	(237)
Stock issued under compensation plans	4	5
Ending balance	(221)	(232)
Common stock, Class A, voting [Member] | Common Stock [Member]
Beginning balance	25	25
Ending balance	25	25
Common stock, Class B, nonvoting [Member] | Common Stock [Member]
Beginning balance	47	47
Ending balance	$ 47	$ 47